A line array swing-scan type optical satellite swing mirror error correction method and system

Abstract

The application provides a line array swing scanning type optical satellite swing mirror error correction method and system, which comprises the following steps: obtaining ground control points on the first swing and the last swing satellite images from high-precision reference data; obtaining connecting points between adjacent two swing satellite images; constructing a line array swing scanning type optical satellite swing mirror error correction model according to the imaging device structure and imaging mechanism of the line array swing scanning type optical satellite; solving line array swing scanning type optical satellite swing mirror error correction parameters by using the control points and the connecting points; and correcting the line array swing scanning type optical satellite swing mirror error by using the swing mirror error correction parameters. The application can realize accurate correction of the line array swing scanning type optical satellite swing mirror error, thereby providing support for high-precision geometric processing of the line array swing scanning type optical satellite image.

Description

Technical Field

[0001] This invention belongs to the technical field of optical satellite data processing, and in particular relates to a method and system for correcting the error of a linear array oscillating optical satellite mirror. Background Technology

[0002] Imaging payloads on linear array oscillating optical satellites typically achieve ultra-wide swath imaging of the Earth's surface by utilizing a 360-degree rotation of a oscillating mirror. Each rotation of the mirror acquires one image. As the satellite progresses along its orbit and the mirror continues to rotate, the payload can acquire several overlapping images. These images are then processed through geometric positioning of individual oscillating images and image stitching between oscillating images in a ground-based processing system to obtain an ultra-wide swath image covering both the orbital and vertical directions.

[0003] Generally, the rotation axis of the pendulum mirror is designed to be along the satellite's flight direction, with the mirror rotating one-dimensionally around this axis. However, in actual imaging processes, factors such as instrument manufacturing processes, instrument installation processes, and instrument performance degradation often make it difficult for the pendulum mirror to precisely rotate one-dimensionally around the axis. The initial and final pendulum angles may also deviate from laboratory measurements. During satellite operation in orbit, the deviation between the actual state of the pendulum mirror and its ideal or designed state inevitably leads to positioning errors in satellite imagery and stitching errors between adjacent pendulum images, ultimately reducing the geometric quality of the satellite image products.

[0004] Linear array sweeping optical imaging satellites are a type of ultra-wide-swath imaging satellite that has only been developed in the last two years. Research on high-precision geometric positioning of linear array sweeping satellites is still in its early stages. How to accurately correct the mirror tilting error of linear array sweeping optical satellites to achieve high-precision positioning of linear array sweeping optical satellite images remains one of the key problems that urgently need to be solved in the high-precision geometric processing of linear array sweeping optical satellite images. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a scheme for correcting the mirror error of a linear array oscillating optical satellite. Based on the imaging device structure and imaging mechanism of the linear array oscillating optical satellite, a mirror error correction model is constructed. By utilizing the ground control points on the satellite images of the first and last oscillating phases and the connection points between adjacent satellite images, the mirror error correction parameters are jointly solved. The obtained correction parameters are then used to accurately correct the mirror error.

[0006] To achieve the above objectives, the present invention provides a method for correcting the error of a linear array oscillating optical satellite mirror, comprising the following steps:

[0007] Step 1: Obtain the ground control points on the satellite imagery of the first and last swings from the high-precision reference data;

[0008] Step 2: Obtain the connection point between two adjacent satellite images;

[0009] Step 3: Based on the imaging device structure and imaging mechanism of the linear array sweeping optical satellite, construct the mirror error correction model for the linear array sweeping optical satellite.

[0010] Step 4: Using control points and connection points, solve for the error correction parameters of the linear array oscillating optical satellite mirrors;

[0011] Step 5: Correct the error of the mirrors in the linear array oscillating optical satellite using the mirror error correction parameters.

[0012] Moreover, the constructed error correction model for the linear array oscillating optical satellite mirror is shown in (1) and (2) below:

[0013]

[0014]

[0015] In the formula, P g P is the position vector of a point on the ground in the Earth-centered Earth-fixed coordinate system. S λ is the position vector of the GNSS antenna phase center in the geocentric-ground-fixed coordinate system; λ is the scaling factor. This is the rotation matrix from the geocentric inertial coordinate system to the geocentric Earth-fixed coordinate system; This is the rotation matrix from the satellite orbital coordinate system to the geocentric inertial coordinate system; This is the rotation matrix from the satellite body coordinate system to the satellite orbit coordinate system; This is the rotation matrix from the imager coordinate system to the satellite body coordinate system; Let be the rotation matrix from the mirror coordinate system to the imager coordinate system, determined by the swing angle. Composition; p = [x, y, -f] T is the position vector of the image point corresponding to the ground point in the tilting mirror coordinate system, (x,y) is the image point coordinate, and f is the principal distance parameter of the satellite imager; α0, α1, α2, α3, β0, β1, β2, β3, θ0, θ1, θ2, θ3 are the correction values ​​for the mirror error; θ0, θ1, θ2, θ3 are the correction parameters for the mirror error.

[0016] Furthermore, the method for solving the error correction parameters of the linear array oscillating optical satellite mirrors includes the following steps.

[0017] Step 4.1, transform equation (1) into:

[0018]

[0019] In the formula, intermediate variables intermediate variables

[0020] Step 4.2: For each ground control point, establish the error equation according to equations (2) and (3):

[0021] Step 4.3: For each connection point between two adjacent images, establish the error equation according to equations (2) and (3).

[0022] Step 4.4: Solve for the unknowns using the least squares adjustment principle;

[0023] Step 4.5: Use the solved unknowns to replace and update the mirror error correction parameters and the geographic coordinates of the connection points;

[0024] Step 4.6: Repeat steps 4.2 to 4.5 until the adjustment iteration converges and the mirror error correction parameters are obtained.

[0025] Moreover, in step 5, the mirror error correction parameters obtained in step 4 are used to correct the satellite mirror error according to equation (2), and then the precise geometric positioning of the linear array sweeping satellite image is achieved according to equation (1).

[0026] On the other hand, the present invention also provides a linear array oscillating optical satellite mirror error correction system, used to implement the linear array oscillating optical satellite mirror error correction method described above.

[0027] Moreover, it includes the following modules,

[0028] The first module is used to obtain ground control points on the satellite imagery of the first and last swings from high-precision reference data;

[0029] The second module is used to obtain the connection point between two adjacent satellite images;

[0030] The third module is used to construct a model for correcting the mirror error of a linear array scanning optical satellite based on the imaging device structure and imaging mechanism of the linear array scanning optical satellite.

[0031] The fourth module is used to solve for the error correction parameters of the linear array oscillating optical satellite mirrors using control points and connection points;

[0032] The fifth module is used to correct the error of the mirrors in a linear array scanning optical satellite using mirror error correction parameters.

[0033] Alternatively, it may include a processor and a memory, with the memory used to store program instructions and the processor used to call the stored instructions in the memory to execute a linear array oscillating optical satellite mirror error correction method as described above.

[0034] Alternatively, it may include a readable storage medium storing a computer program that, when executed, implements a linear array oscillating optical satellite mirror error correction method as described above.

[0035] Compared with the prior art, the present invention has the following advantages: Based on the physical structure and imaging mechanism of the linear array oscillating optical satellite, the present invention constructs a model for correcting the oscillating mirror error of the linear array oscillating optical satellite, and makes full use of the absolute control provided by the ground control points and the relative control provided by the inter-oscillating connection points to solve the oscillating mirror error correction parameters, thereby achieving accurate correction of the oscillating mirror error of the linear array oscillating optical satellite, thus providing support for accurate geometric processing of linear array oscillating optical satellite images. Attached Figure Description

[0036] Figure 1 This is a flowchart of an embodiment of the present invention. Detailed Implementation

[0037] This invention provides a method for correcting the mirror error of a linear array sweeping optical satellite. First, ground control points on the first and last sweeping satellite images are obtained from high-precision reference data using image matching or manual measurement methods. Second, connection points between adjacent sweeping satellite images are obtained using image matching or manual measurement methods. Then, based on the imaging device structure and imaging mechanism of the linear array sweeping optical satellite, a mirror error correction model is constructed. Next, using the control points and connection points, the mirror error correction parameters are solved. Finally, the mirror error correction parameters are used to correct the mirror error of the linear array sweeping optical satellite, achieving accurate mirror error correction.

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] like Figure 1 As shown, the error correction method for a linear array oscillating optical satellite mirror provided by this embodiment of the invention includes the following steps:

[0040] Step 1: Using image matching or manual measurement methods, obtain the ground control points on the satellite images of the first and last swings from the high-precision reference data;

[0041] Step 2: Use image matching or manual measurement methods to obtain the connection points between two adjacent satellite images;

[0042] Step 3: Based on the imaging device structure and imaging mechanism of the linear array sweeping optical satellite, construct the mirror error correction model for the linear array sweeping optical satellite, as shown in equations (1) and (2):

[0043]

[0044]

[0045] In the formula, P g P is the position vector of a point on the ground in the Earth-centered Earth-fixed coordinate system. S λ is the position vector of the GNSS antenna phase center in the geocentric-ground-fixed coordinate system; λ is the scaling factor. This is the rotation matrix from the geocentric inertial coordinate system to the geocentric Earth-fixed coordinate system; This is the rotation matrix from the satellite orbital coordinate system to the geocentric inertial coordinate system; This is the rotation matrix from the satellite body coordinate system to the satellite orbit coordinate system; This is the rotation matrix from the imager coordinate system to the satellite body coordinate system; Let be the rotation matrix from the mirror coordinate system to the imager coordinate system, determined by the swing angle. Composition; p = [x, y, -f] T is the position vector of the image point corresponding to the ground point in the tilting mirror coordinate system, (x,y) is the image point coordinate, and f is the principal distance parameter of the satellite imager; α0, α1, α2, α3, β0, β1, β2, β3, θ0, θ1, θ2, θ3 are the correction values ​​for the mirror error; θ0, θ1, θ2, θ3 are the correction parameters for the mirror error.

[0046] Step 4: Using control points and connection points, solve for the error correction parameters of the linear array oscillating optical satellite mirrors. This includes the following steps:

[0047] Step 4.1, transform equation (1) into:

[0048]

[0049] In the formula, intermediate variables intermediate variables

[0050] Step 4.2: For each ground control point, establish the error equation according to equations (2) and (3):

[0051] V g =A g XL g (4)

[0052] In the formula, This is the residual matrix of the ground control points; The correction matrix for the unknowns; The design matrix is ​​composed of the partial derivatives of the unknowns; Let g be a constant term matrix; where the subscript g represents a ground control point, and the subscripts i and j represent the j-th ground control point on the i-th sculpted image. Then (xg,i,j ,y g,i,j Let be the image coordinates of the j-th ground control point on the i-th image. These are the initial values ​​for the image point coordinates. Let be the residual of the image coordinates of the ground control points, and (dα0,dα1,dα2,dα3,dβ0,dβ1,dβ2,dβ3,dθ0,dθ1,dθ2,dθ3) be the correction value of the mirror error correction parameter (α0,α1,α2,α3,β0,β1,β2,β3,θ0,θ1,θ2,θ3). This indicates the calculation of partial derivatives.

[0053] If there are N pendulum images in total, numbered from 1 to N, in step 4.2, i can take values ​​of 1 (first pendulum) and N (last pendulum); in step 4.3, i can take values ​​from 1 to N.

[0054] Step 4.3: For each connection point between two adjacent image pairs, establish the error equation according to equations (2) and (3):

[0055] V t =A t X+C t YL t (5)

[0056] In the formula, V t A t L t The meaning is the same as in formula (4); The design matrix is ​​composed of the partial derivatives of the unknowns. Let be the correction matrix for the unknowns; where the subscript t represents the connection point, and the subscripts i and k represent the k-th connection point on the i-th pendulum image, (dΩ j ,dΦ j ) represents the longitude coordinates of the connection point Ω j and latitude coordinates Φ j number of corrections.

[0057] Step 4.4, solve for the unknowns X and Y according to the least squares adjustment principle:

[0058]

[0059] In the formula, each intermediate variable

[0060] Step 4.5: Using X and Y obtained from equation (6), the mirror error correction parameters and the geographic coordinates of the connection point are replaced and updated, as shown in equation (7).

[0061]

[0062] In the formula, s is the number of iterations, i.e.

[0063] and These are the mirror error correction parameters obtained from the (s-1)th iteration and the sth iteration, respectively. and These are the geographic coordinates of the connection point obtained in the (s-1)th and sth iterations, respectively.

[0064] Step 4.6: Repeat steps 4.2 to 4.5 until the adjustment iteration converges and the mirror error correction parameters are obtained.

[0065] Step 5: Using the mirror error correction parameters obtained in Step 4, the satellite mirror error is corrected according to Equation (2), and then the precise geometric positioning of the linear array sweeping satellite image can be achieved according to Equation (1).

[0066] Thus, the error correction parameters for the linear array oscillating optical satellite mirror are obtained, enabling precise error correction of the linear array oscillating optical satellite mirror, and the error correction work for the linear array oscillating optical satellite mirror is completed.

[0067] In specific implementation, the method proposed in the technical solution of this invention can be automatically executed by those skilled in the art using computer software technology. System devices for implementing the method, such as computer-readable storage media storing the corresponding computer program of the technical solution of this invention and computer equipment including the computer program running the corresponding computer program, should also be within the protection scope of this invention.

[0068] In some possible embodiments, a linear array oscillating optical satellite mirror error correction system is provided, comprising the following modules:

[0069] The first module is used to obtain ground control points on the satellite imagery of the first and last swings from high-precision reference data;

[0070] The second module is used to obtain the connection point between two adjacent satellite images;

[0071] The third module is used to construct a model for correcting the mirror error of a linear array scanning optical satellite based on the imaging device structure and imaging mechanism of the linear array scanning optical satellite.

[0072] The fourth module is used to solve for the error correction parameters of the linear array oscillating optical satellite mirrors using control points and connection points;

[0073] The fifth module is used to correct the error of the mirrors in a linear array scanning optical satellite using mirror error correction parameters.

[0074] In some possible embodiments, a linear array oscillating optical satellite mirror error correction system is provided, including a processor and a memory. The memory is used to store program instructions, and the processor is used to call the stored instructions in the memory to execute a linear array oscillating optical satellite mirror error correction method as described above.

[0075] In some possible embodiments, a linear array oscillating optical satellite mirror error correction system is provided, including a readable storage medium storing a computer program, which, when executed, implements the linear array oscillating optical satellite mirror error correction method as described above.

[0076] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for correcting errors in a linear array oscillating optical satellite mirror, characterized in that, Includes the following steps: Step 1: Obtain the ground control points on the satellite imagery of the first and last swings from the high-precision reference data; Step 2: Obtain the connection point between two adjacent satellite images; Step 3: Based on the imaging device structure and imaging mechanism of the linear array sweeping optical satellite, construct the mirror error correction model for the linear array sweeping optical satellite. Step 4: Using the absolute control provided by the ground control points and the relative control provided by the inter-swing connection points, solve for the error correction parameters of the linear array oscillating optical satellite mirrors; Step 5: Correct the error of the mirrors in the linear array oscillating optical satellite using the mirror error correction parameters; The constructed error correction models for the linear array oscillating optical satellite mirrors are shown in (1) and (2) below: （1） （2） In the formula, This is the position vector of a point on the ground in the Earth-centered Earth-fixed coordinate system; This is the position vector of the GNSS antenna phase center in the geocentric-ground-fixed coordinate system; It is a scaling factor; This is the rotation matrix from the geocentric inertial coordinate system to the geocentric Earth-fixed coordinate system; This is the rotation matrix from the satellite orbital coordinate system to the geocentric inertial coordinate system; This is the rotation matrix from the satellite body coordinate system to the satellite orbit coordinate system; This is the rotation matrix from the imager coordinate system to the satellite body coordinate system; Let be the rotation matrix from the mirror coordinate system to the imager coordinate system, determined by the swing angle. constitute; Let be the position vector of the image point corresponding to the ground point in the mirror coordinate system. For image point coordinates, For the main distance parameter of the satellite imager; This is the correction value for the mirror tilting error; For the correction parameters of the tilting mirror error; The method for solving the error correction parameters of the linear array oscillating optical satellite mirror includes the following steps. Step 4.1, transform equation (1) into: （3） In the formula, intermediate variables ; intermediate variables ; Step 4.2, for each ground control point, establish the error equation according to equations (2) and (3): Step 4.3: For each connection point between two adjacent images, establish the error equation according to equations (2) and (3); Step 4.4: Solve for the unknowns using the least squares adjustment principle; Step 4.5: Use the solved unknowns to replace and update the mirror error correction parameters and the geographic coordinates of the connection points; Step 4.6: Repeat steps 4.2 to 4.5 until the adjustment iteration converges and the mirror error correction parameters are obtained.

2. The method for correcting the error of a linear array oscillating optical satellite mirror as described in claim 1, characterized in that: In step 5, the mirror error correction parameters obtained in step 4 are used to correct the satellite mirror error according to equation (2), and then the precise geometric positioning of the linear array sweeping satellite image is achieved according to equation (1).

3. A linear array oscillating sweeping optical satellite mirror error correction system, characterized in that: This method is used to implement the error correction method for linear array oscillating optical satellite mirrors as described in any one of claims 1-2. Includes the following modules, The first module is used to obtain ground control points on the satellite imagery of the first and last swings from high-precision reference data; The second module is used to obtain the connection point between two adjacent satellite images; The third module is used to construct a model for correcting the mirror error of a linear array scanning optical satellite based on the imaging device structure and imaging mechanism of the linear array scanning optical satellite. The fourth module is used to solve for the error correction parameters of the linear array oscillating optical satellite mirrors using control points and connection points; The fifth module is used to correct the error of the mirrors in a linear array scanning optical satellite using mirror error correction parameters.

4. A linear array oscillating scanning optical satellite mirror error correction system, characterized in that: It includes a processor and a memory, the memory being used to store program instructions, and the processor being used to call the stored instructions in the memory to execute the linear array oscillating optical satellite mirror error correction method as described in any one of claims 1-2.

5. A readable storage medium, characterized in that: The readable storage medium stores a computer program, which, when executed, implements a method for correcting the error of a linear array oscillating optical satellite mirror as described in any one of claims 1-2.

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